At the top of Monks Mound, evidence suggests there was once a substantial building — perhaps 30 meters long and 15 meters wide, making it larger than many medieval European churches.

The building is gone, its wood long since rotted.

But the prepared surface on which it stood, and the post holes and debris that indicate its former presence, have been detected through excavation.

Monks Mound was the center of a planned urban landscape.

Around it, within a central precinct that was bounded by a large wooden palisade — a stockade wall nearly 3 kilometers long, constructed from tens of thousands of wooden posts — were other major mounds, open plazas, and the residences of the people who occupied the city’s core.

Archaeological evidence indicates that the palisade was rebuilt at least four times, suggesting both long occupation and periodic renovation of the city’s central defenses.